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OBJECTIVE@#To analyze recurrence and progression patterns of primary central nervous system lymphoma (PCNSL) in patients without whole brain radiotherapy (WBRT) and assess the value of WBRT in PCNSL treatment.@*METHODS@#This retrospective single-center study included 27 patients with PCNSL, who experienced recurrence/progression after achieving complete remission (CR), partial remission, or stable disease following initial treatments with chemotherapy but without WBRT. The patients were followed up regularly after the treatment for treatment efficacy assessment. By comparing the anatomical location of the lesions on magnetic resonance images (MRI) at the initial diagnosis and at recurrence/progression, we analyzed the patterns of relapse/progression in patients with different treatment responses and different initial status of the lesions.@*RESULTS@#MRI data showed that in 16 (59.26%) of the 27 patients, recurrence/progression occurred in out-field area (outside the simulated clinical target volume [CTV]) but within the simulated WBRT target area in 16 (59.26%) patients, and within the CTV (in-field) in 11 (40.74%) patients. None of the patients had extracranial recurrence of the tumor. Of the 11 patients who achieved CR after the initial treatments, 9 (81.82%) had PCNSL recurrences in the out-field area but within WBRT target area; of the 13 patients with a single lesion at the initial treatment, 11 (84.62%) experienced PCNSL recurrence in the out-field area but within WBRT target area.@*CONCLUSIONS@#Systemic therapy combined with WBRT still remains the standard treatment for PCNSL patients, especially those who achieve CR after treatment or have a single initial lesion. Future prospective studies with larger sample sizes are needed to further explore the role of low-dose WBRT in PCNSL treatment.
Subject(s)
Humans , Lymphoma/radiotherapy , Central Nervous System Neoplasms/pathology , Retrospective Studies , Prospective Studies , Neoplasm Recurrence, Local/drug therapy , Combined Modality Therapy , Brain/pathology , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , MethotrexateABSTRACT
Whole brain radiotherapy (WBRT) is the standard radiotherapy regimen of preventive radiation for patients diagnosed with brain metastases and non-small cell lung cancer, which can improve intracranial control and prolong overall survival. However, neurocognitive functions (NCF) decline due to impaired hippocampal might occur thereafter. Recent studies have shown that hippocampal sparing WBRT (HS-WBRT) is capable of protecting neurocognitive function and improving quality of life (QOL). In this review, the authors described the methods and significance of hippocampal sparing, summarized the research progress on clinical trials related to HS-WBRT in combination with the development of radiotherapy technology and experimental drugs, and discussed the existing controversies and problems, aiming to provide reference for clinical work.
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Objective:To compare the dosimetric differences between the VenusX accelerator with an orthogonal dual-layer multi-leaf collimator (MLC) and the Varian′s CLINAC IX and EDGE accelerators with a single-layer MLC for hippocampus protection in the whole-brain radiotherapy (WBRT).Methods:Forty patients with multiple brain metastases admitted to the Radiotherapy Department of the Shanghai General Hospital from June 2021 to February 2023 were selected in this study. Three whole-brain treatment plans were designed based on the above three accelerators for each patient. Under the same prescription dose, radiation field, and plan constraints, the three plans were compared in terms of the dosimetric differences in target volumes, hippocampi, and adjacent organs at risk (OARs), as well as the execution efficiency.Results:For the planning target volume (PTV), there were statistically significant differences in approximate maximum dose ( D2) between the VenusX and IX plans ( t = 4.94, P < 0.05), in approximate minimum dose ( D98) between the VenusX and EDGE plans ( t = 5.98, P < 0.05), in the target conformity indices (CIs) between VenusX plan and EDGE plans, and between the VenusX and IX plans ( t = -6.84, -14.30; P < 0.05), and dose homogeneity indices (HIs) between the VenusX and IX plans ( t = 3.48, P < 0.05). For OARs, the maximum doses ( Dmax) and average doses ( Dmean) to bilateral hippocampi of the VenusX plan were lower than those of the EDGE and IX plans ( t = 8.59-17.11, P < 0.05); the maximum doses ( Dmax) to bilateral lenses, bilateral optic nerves, and optic chiasma of the VenusX plan were lower than those of the other two plans ( t = 2.10-20.80, P < 0.05); and the differences between the maximum doses ( Dmax) to the brain stem of the VenusX and EDGE plans were statistically significant ( t = 3.86, P < 0.05). In terms of plan execution efficiency, the number of machine jumps (MU) and the treatment time of the VenusX plan were higher than those of the EDGE and IX plans, with statistically significant differences ( t = -56.48, -56.90, P < 0.05). Conclusions:The doses to target volumes of the three treatment plans all meet the prescription requirements, and the VenusX plan outperforms the EDGE and IX plans in the protection of OARs. Despite the reduced execution efficiency, the VenusX plan shortens the actual treatment time by improving the dosage rate, thus meeting the clinical requirements.
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Lung cancer is the malignant tumor with the highest incidence and mortality in China, and is prone to brain metastasis in the process of disease development, which seriously affects the quality of life and survival of patients. The treatment methods for brain metastasis of lung cancer include surgery, chemotherapy, whole brain radiotherapy, stereotactic radiosurgery, molecular targeted therapy, immunotherapy, anti-angiogenesis therapy, etc. It's one of the research hotspots to choose reasonable and effective treatment schemes for different patients. This paper reviews the research progress in the treatment of brain metastasis from lung cancer, to provide reference for selecting more reasonable clinical treatment for the patients.
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@#<b>Objective</b> To compare the dosimetric differences of volumetric modulated arc therapy (VMAT) with flattening filter(FF) and flattening filter-free(FFF) modes in hippocampal avoidance whole brain radiotherapy. <b>Methods</b> We included 15 patients with hippocampal-sparing whole brain radiotherapy, and designed two radiotherapy plans of FF-VMAT and FFF-VMAT for each patient. On the premise of meeting clinical dose requirements, the two plans’ dosimetry, total number of monitor units, and beam-on time were compared. <b>Results</b> There were no significant differences in the target coverage, conformity index, and dose gradient of the FF-VMAT and FFF-VMAT plans (<i>P</i> > 0.05). The <i>D</i><sub>max</sub>, <i>D</i><sub>100%</sub>, and <i>D</i><sub>mean</sub><sub> </sub>to the hippocampal tissue were significantly lower with FFF-VMAT [(15.13 ± 0.38) Gy, (7.12 ± 0.34) Gy, and (9.76 ± 0.43) Gy, respectively)] than with FF-VMAT (16.46 ± 0.56) Gy, (7.72 ± 0.28) Gy, and (10.54 ± 0.48) Gy, respectively)] (<i>P</i> < 0.05). The <i>D</i><sub>max</sub><sub> </sub>to the left and right lenses and the <i>D</i><sub>mean</sub><sub> </sub>to the left and right eyeballs with FFF-VMAT were (7.26 ± 0.43) Gy, (6.29 ± 1.13) Gy, (11.01 ± 0.94) Gy, and (9.78 ± 1.13) Gy, respectively, which were significantly lower than FF-VMAT’s corresponding doses of (8.09 ± 0.66) Gy, (7.80 ± 0.74) Gy, (11.38 ± 1.09) Gy, and (11.05 ± 0.90) Gy, respectively (<i>P</i> < 0.05). The doses to other organs at risk including the optic nerve and optic chiasm were all controlled within the safe dosage ranges, with no significant differences between the two plans (<i>P</i> > 0.05). The FFF-VMAT plan had a significantly greater number of monitor units and a significantly shorter beam-on time than the FF-VMAT plan (<i>P</i> < 0.05). <b>Conclusion</b> Both FF-VMAT and FFF-VMAT can meet the clinical requirements, with FFF-VMAT having better hippocampus and lens protection, shorter beam-on time, and higher treatment efficiency.
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Objective:To analyze the prognosis and influencing factors of patients with brain metastases from non-small cell lung cancer (NSCLC) treated with different doses of whole brain radiotherapy (WBRT).Methods:A total of 244 NSCLC patients with brain metastases who underwent WBRT in the Fourth Hospital of Hebei Medical University from 2013 to 2015 were analyzed retrospectively. According to different doses of WBRT (EQD 2Gy), they were divided into the 30-39 Gy group ( n= 104) and ≥40 Gy group ( n= 140). The intracranial progression-free survival (iPFS) and overall survival (OS) were compared betweentwo groups. According to the number of brain metastases, GPA score, KPS score, chemotherapy and targeted therapy, the prognosis of different doses of WBRT was further analyzed. Results:The median iPFS and OS of all patients were 6.9 months and 11.8 months, respectively. Univariate survival analysis: the 1-year iPFS and 1-year OS between two groups were 22.5% and 25.4%( P=0.430) and 41.1% and 46.4%( P=0.068), respectively. Multivariate survival analysis: different doses of WBRT were not associated with the improvement of iPFS and OS; independent factors influencing iPFS included local boost, gender, number of brain metastases, chemotherapy and targeted therapy; independent factors influencing OS included gender, number of brain metastases, chemotherapy and targeted therapy. Subgroup analysis: in patients with KPS≥90, the 1-year iPFS and OS of patients with WBRT ≥ 40 Gy were seemingly better than those of their counterparts with 30-39 Gy, but the difference was statistically significant only in OS ( P=0.047), the difference was not statistically significant in iPFS ( P=0.068); in patients with chemotherapy, the 1-year iPFS and OS of patients with WBRT≥40 Gy were better than those of their counterparts with 30-39 Gy ( P=0.017, P=0.012); in patients with targeted therapy, the 1-year iPFS and OS in the WBRT≥40 Gy group were better than those in the 30-39 Gy group ( P=0.012, P=0.045). Conclusions:The 30-39 Gy may be the appropriate dose of WBRT for NSCLC patients with brain metastases. WBRT≥40 Gy does not bring more benefits. WBRT≥40 Gy may benefit NSCLC patients with brain metastases with high KPS score or active systemic therapy.
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Objective:To analyze the prognosis and influencing factors of different radiotherapy modes in patients with brain metastases from non-small cell lung cancer (NSCLC), and to explore the best benefit population with radiotherapy boost under different prognostic scores.Methods:634 patients with brain metastasis from NSCLC admitted to the Fourth Hospital of Hebei Medical University from 2013 to 2015 were analyzed retrospectively. According to different radiotherapy modes, they were divided into three groups: no radiotherapy group ( n=330), whole-brain radiotherapy group (WBRT)( n=127) and whole-brain radiotherapy combined with boost group (WBRT+ boost)( n=177). The intracranial progression-free survival (iPFS) and overall survival (OS) were calculated by Kaplan-Meier method. The multivariate prognostic factors were analyzed by the Cox models. Results:The median iPFS and OS of all patients were 6.9 months and 9.0 months, respectively. In the no radiotherapy, WBRT and WBRT+ boost groups, the 1-year iPFS was 15.1%, 16.3% and 40.2%( P=0.002), and the 1-year OS was 33.7%, 38.2% and 48.1%( P<0.001), respectively. Multivariate survival analysis demonstrated that different radiotherapy modes were the independent factors affecting iPFS and OS. Subgroup analysis revealed that for patients with 1-3 brain metastases, the 1-year OS and iPFS in the WBRT+ boost group were better than those of WBRT alone ( P=0.026, P=0.044) when GPA score was 2.5-4.0; the 1-year OS and iPFSin the WBRT+ boost group were better than those of WBRT alone ( P=0.036, P=0.049) when there was no targeted therapy; for patients with ≥4 brain metastases, the 1-year iPFS in the WBRT+ boost group was better than that of WBRT alone ( P=0.019, P=0.012) when GPA score was 2.5-4.0 and there was no targeted therapy. When the GPA score was 0-2 or there was targeted therapy, the 1-year OS and iPFS in the WBRT+ boost group were better than those of WBRT alone, but the difference was not statistically significant (all P>0.05). Conclusions:Radiotherapy can significantly improve the iPFS and OS of NSCLC patients with brain metastases. When the number of brain metastases is 1-3, GPA score is 2.5-4.0 or no targeted therapy, boost may improve the iPFS and OS; when the number of brain metastases is more than 4, GPA score is 2.5-4.0 or no targeted therapy, boost may only bring iPFS benefit; when GPA score is 0-2 or targeted therapy, boost may not benefit significantly.
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Objective The purpose of this study is to provide a reference for the selection of clinical radiotherapy plan by comparing the difference of dosimetry between coplanar dynamic intensity modulation dIMRT and coplanar VMAT plan in hippocampal protective whole brain radiotherapy (WBRT). Methods 10 patients were selected whose hippocampal were protected by WBRT, dIMRT and VMAT plans were designed for each patient, the differences of target dose, organ-endangering dose and machine hop count were compared between the two groups. Results The two technical plans PTV V30 Gy, D98% and D2% all meet the standard of RTOG 0933, which is better than the dIMRT group for the PTV HI VMAT group (P = 0.004). The hippocampal dose of dIMRT group was better than that of VMAT group, but it did not meet the standard of RGOT 0933. The average Dmax of hippocampus in dIMRT group and VMAT group was 18.44 Gy and 19.30 Gy, respectively (P = 0.004). The average value of hippocampal Dmin was 10.03 Gy and 10.77 Gy, respectively (P = 0.013), and the mean value of hippocampal Dmean was 14.20 Gy and 15.12 Gy, respectively (P = 0.002). The doses of lens, eyeball and optic nerve all met the standard of RTOG0933, and the dose of dIMRT group was significantly better than that of VMAT group (P = 0.000). The treatment time in VMAT group was significantly lower than that in dIMRT group. The treatment time in VMAT group was significantly lower than that in dIMRT group. Conclusion Varian dIMRT has more advantages in controlling hippocampal dose and protecting lens than VMAT, but PTV HI and treatment efficiency are higher in VMAT group.
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With the advancement of imaging diagnosis and the development of modern radiotherapy, the survival of cancer patients has been prolonged and the incidence rate of brain metastases (BM) has been significantly increased. The quality of life of patients and potential radiotherapy-induced neurocognitive impairment have gradually captivated widespread attention. Whole brain radiotherapy (WBRT) is one of the common local therapies for BM patients. However, the application of WBRT is controversial because it may lead to neurocognitive impairment. The incidence of metastatic tumors in hippocampus and radiation-induced neurocognitive impairment can accelerate the implementation of hippocampal-avoidance WBRT (HA-WBRT). In this article, the feasibility of HA-WBRT was discussed and research progress in recent years was reviewed.
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The efficacy of treatments in patients with nonsmall cell lung cancer (NSCLC) with leptomeningeal metastases (LMs) remains unclear. Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) play an important role in the treatment of patients with NSCLC. However, few studies have investigated the efficacy of combination therapy with TKIs and whole brain radiotherapy (WBRT) in patients with NSCLC/LM. We report here the case of a male patient in his 60s with adenocarcinoma who underwent lobectomy of the right upper lobe. The cancer was classified as pT1bN1M0 Stage IIA, and a mutational analysis revealed the presence of an EGFR mutation. However, 6 months after standard chemotherapy, LM had developed and WBRT was administered. Gefitinib (250 mg/day) was administered after WBRT. The patient remained free of significant recurrent disease for 57 months after WBRT was administered. Combination therapy with TKIs and WBRT is associated with relatively long survival times in patients with LM
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Introducción: Las metástasis cerebrales constituyen una causa importante de mortalidad y son los tumores intracraneales más comunes en adultos, ocurren en aproximadamente el 20% y el 40% de los pacientes diagnosticados con cáncer. Los factores pronósticos que permiten estimar la esperanza de vida, son las herramientas que se deberían usar para proponer el fraccionamiento y duración del tratamiento con energía radiante. Métodos: Estudio de tipo retrospectivo realizado en el Hospital de Solón Espinosa Ayala, SOLCA-Quito. Se registraron los pacientes con metástasis cerebrales tratados con radioterapia holoencefálica en el período comprendido entre enero del 2003 a diciembre del 2018. Para el análisis de supervivencia se usaron las curvas de Kaplan Meier y la significación de diferencias con la prueba de Long-rank con un error tipo I o alfa del 5%. Además se realizó un análisis bivariado con el modelo de regresión logística de Cox entre la mediana de supervivencia y las variables: Indice de Karnofsky (IK), edad, número de metástasis cerebrales, metástasis extracraneales, tumor primario y la escala "Graded Prognostic Assessment" (GPA). Resultados: Se registraron309 pacientes, la mediana de supervivencia global fue de 5 meses. Todos los factores afectan la supervivencia (p ≤0.05); los que alcanzaron los mejores resultados en términos de sobrevida fueron: IK ≥90, grupo etario entre 51-60 años, los pacientes con 1 metástasis cerebral, ausencia de metástasis extra craneales y las metástasis cerebrales originadas en mama con puntuaciones de GPA entre 3.5-4. Conclusión: La edad, el índice de Karnofsky, el número de metástasis cerebrales, la presencia de metástasis extra craneales, tumor primario y clasificación GPA son factores que permiten estimar el tiempo de supervivencia en pacientes con metástasis cerebrales
Introduction: Brain metastases are an important cause of mortality and the most common intracranial tumors in adults, observed in approximately 20% and 40% of patients diagnosed with cancer. The prognostic factors that allow estimating life expectancy are the tools that should be used to propose the fractionation and duration of the radiant energy treatment. Methods: The present retrospective study was carried out at the Solón Espinosa Ayala Hospital, SOLCA-Quito. The patients who received whole brain radiotherapy in the study period from January 2003 to December 2018, were registered. For survival analysis, use the Kaplan Meier curves and the significance of differences with the long-range test with a 5% type I or alpha error. In addition, a bivariate analysis was performed with the Cox logistic regression model between the median survival and the variables: Karnofsky index (IK), age, number of brain metastases, extracranial metastases, primary tumor and the "Graded Prognostic Assessment" (GPA). Results: 309 patients were registered and the median overall survival of patients with brain metastases treated with whole brain radiotherapy was 5 months. All factors affect survival (p ≤ 0.05); those who achieved the best results in terms of survival were: Karnofsky Performance Status (KPS) ≥ 90, age group between 51-60 years, patients with 1 brain metastasis, absence of extracranial metastases and brain metastases originated in breasts with Graded Prognostic Assessment (GPA) score between 3.5- 4. Conclusion: Age, KPS, number of brain metastases, presence of extracranial metastases, primary tumor and GPA are factors that allow estimating survival time in patients with brain metastases
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Humans , Prognosis , Cerebrum , Neoplasm Metastasis , Survival , Brain NeoplasmsABSTRACT
Background: Brain metastases are the most common intracranial malignancy in adults and their management poses a significant healthcare problem. Of the various options available, whole brain radiotherapy (WBRT) remains the mainstay of treatment. Nonetheless, there is a need to develop fractionation schedules for best symptom palliation and prolonged survival. This prospective study aims to compare treatment outcome in terms of overall survival in two different WBRT schedules and determine the prognostic factors affecting this outcome.Methods: Sixty previously untreated patients with symptomatic brain metastases were randomized in two arms of 30 patients each to receive WBRT. Arm A patients received 30Gy in 10 fractions (long-course) and arm B received 20Gy in 5 fractions (short-course). All patients were assessed during and after completion of WBRT at 1, 3, 6, 9 and 12 months.Results: At 12 months post WBRT, the objective response rate i.e. complete and partial response (CR+PR) was 6.67% in arm A and 13.34% in arm B (p=0.96). Both WBRT regimens showed similar survival (p=0.65). On multivariate linear regression analysis, age ≤65 years, Karnofsky performance score (KPS) ≥70 and lack of extra-cranial metastases were significantly associated with improved survival at the end of 12 months post WBRT. EORTC QLQ-C30 showed similar improvement in quality of life in both the arms (p=0.86).Conclusions: This study suggests comparable results in the two fractionation schedules. Therefore, short-course WBRT may be used as a more convenient option in favour of shorter hospital stay and lesser burden on RT machines.
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Objective@#To explore the intensity of coplanar arc-adjusted radiotherapy with volume-modulated arc therapy (VMAT) and whether the position of the head tilt influences the distribution of radiotherapy dose.@*Methods@#From 2015 to 2017, 500 patients underwent radiotherapy of the head and kept their head tilted. The simulated non-inclined CT images were obtained by rotating the original CT images. The protocol of the coplanar VMAT whole brain irradiation was 30 Gy and the maximum dose of planning target volume in the hippocampus was limited to 16 Gy. The doses of the optic nerve, optic chiasm and eyeball were lower than 37.5 Gy. The dosimetric parameters of two different protocols were statistically compared by paired t-test.@*Results@#The average head tilt angle was (11.12°±0.68°). The homogeneity and the conformal index in the tilted and non-tilted positions were decreased by (8.3±9.6)%(P=0.033) and (5.2±4.1)%(P=0.009). The dose of hippocampus in the tilted position of the head was decreased by (13.6±6.2)% on average compared with that in the non-inclined position (P=0.004). The dose of the lenses was decreased by (15.5±11.1)%(P=0.008) on average. The doses of optic nerve and eyeball were declined by (6.8±5.6)%(P=0.013) and (8.6±6.5)%(P=0.016).@*Conclusions@#By tilting the head at an appropriate angle during VMAT whole-brain radiotherapy, the radiation dose distribution of the target volume can be significantly improved and the radiation dose in the hippocampus and visual system can be reduced simultaneously to maintain the therapeutic effect and minimize the effect upon the cognitive and memory function of patients.
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Whole brain radiotherapy (WBRT) was widely used clinically as the standard therapy for brain metastases (BM). With the development of radiotherapy technology and systemic therapies, the non-small cell lung cancer (NSCLC) patients have prolonged local control rate and median survival time, meanwhile post-radiotherapy intracranial toxicities often lead to serious impacts on the quality of life and neurocognitive function. Therefore, the role WBRT played should have been reevaluated. The purpose of this review is to analyze the clinical application value of WBRT in the context of new treatments for NSCLC with BM, and to predict the main developing directions of WBRT in the future.
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Whole brain radiotherapy (WBRT) was widely used clinically as the standard therapy for brain metastases (BM).With the development of radiotherapy technology and systemic therapies,the nonsmall cell lung cancer (NSCLC) patients have prolonged local control rate and median survival time,meanwhile post-radiotherapy intracranial toxicities often lead to serious impacts on the quality of life and neurocognitive function.Therefore,the role WBRT played should have been reevaluated.The purpose of this review is to analyze the clinical application value of WBRT in the context of new treatments for NSCLC with BM,and to predict the main developing directions of WBRT in the future.
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PURPOSE: Lung Cancer Subcommittee of Korean Radiation Oncology Group (KROG) has recently launched a prospective clinical trial (KROG 17-06) of hippocampus-sparing whole brain radiotherapy (HS-WBRT) with simultaneous integrated boost (SIB) in treating multiple brain metastases from non-small cell lung cancer. In order to improve trial quality, dummy run studies among the participating institutions were designed. This work reported the results of two-step dummy run procedures of the KROG 17-06 study. MATERIALS AND METHODS: Two steps tested hippocampus contouring variability and radiation therapy planning compliance. In the first step, the variation of the hippocampus delineation was investigated for two representative cases using the Dice similarity coefficients. In the second step, the participating institutions were requested to generate a HS-WBRT with SIB treatment plan for another representative case. The compliance of the treatment plans to the planning protocol was evaluated. RESULTS: In the first step, the median Dice similarity coefficients of the hippocampus contours for two other dummy run cases changed from 0.669 (range, 0.073 to 0.712) to 0.690 (range, 0.522 to 0.750) and from 0.291 (range, 0.219 to 0.522) to 0.412 (range, 0.264 to 0.598) after providing the hippocampus contouring feedback. In the second step, with providing additional plan priority and extended dose constraints to the target volumes and normal structures, we observed the improved compliance of the treatment plans to the planning protocol. CONCLUSION: The dummy run studies demonstrated the notable inter-institutional variability in delineating the hippocampus and treatment plan generation, which could be decreased through feedback from the trial center.
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Brain , Carcinoma, Non-Small-Cell Lung , Compliance , Hippocampus , Lung Neoplasms , Neoplasm Metastasis , Prospective Studies , Radiation Oncology , RadiotherapyABSTRACT
BACKGROUND: The purpose of this study was to evaluate the efficacy and feasibility of non-coplanar whole brain radiotherapy (NC-WBRT) for parotid sparing.METHODS: Fifteen cases, previously treated with WBRT were selected. NC-WBRT plans were generated. The beam arrangement for the non-coplanar plans consisted of superior anterior, right, and left beams. After generation of the non-coplanar plans a field-in-field technique was applied to the bilateral parallel opposed beams in order to reduce maximum dose and increase dose homogeneity. The NC-WBRT plans were subsequently compared with the previously generated bilateral WBRT (B-WBRT) plans. A field-in-field technique was also used with the B-WBRT plans according to our departmental protocol. As per our institutional practice a total dose of 30 Gy in 10 fractions of WBRT was administered 5 days a week.RESULTS: The mean dose to the parotid gland for the two different plans were 16.2 Gy with B-WBRT and 13.7 Gy with NC-WBRT (p < 0.05). In the NC-WBRT plan, the V5Gy, V10Gy, V15Gy, V20Gy, and V25Gy of the parotid were significantly lower (p < 0.05) than those of the B-WBRT plan. The Dmax of the lens was also lower by 10% with NC-WBRT.CONCLUSION: The use of NC-WBRT plans could be a simple and effective method to reduce irradiated volumes and improve the dose-volume parameters of the parotid gland.
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Brain , Institutional Practice , Methods , Parotid Gland , Radiotherapy , XerostomiaABSTRACT
PURPOSE: The aim of this study is to evaluate the efficacy and feasibility of four-field box whole brain radiotherapy (FB-WBRT) with tilting baseplate by comparing bilateral WBRT (B-WBRT). METHODS AND MATERIALS: Between March 2016 and September 2018, 20 patients with brain metastases underwent WBRT using the four-field box technique. WBRT is performed with a dose of 30 Gy in 10 fractions daily. Two computed tomography simulations per person were performed. One was in the traditional supine position for B-WBRT and the other by applying the tilting acrylic supine baseplate to elevate the head by 40° for FB-WBRT. The B-WBRT used the field-in-field technique, which is the most commonly used method in our institution. The FB-WBRT comprised anterior, posterior, and bilateral beams. A wedge was applied in anterior and posterior fields to compensate for skull convexity. RESULTS: The average of Dmean of both parotid glands was 10.2 Gy (range, 3.8 to 17.8 Gy) in B-WBRT and 5.4 Gy (range, 2.0 to 11.7 Gy) in FB-WBRT (p < 0.05). Compared to B-WBRT, FB-WBRT reduced the mean dose of the right and left parotid glands from 10.1 Gy to 4.9 Gy and from 10.4 Gy to 5.8 Gy, respectively (p < 0.05). Further, V₅, V₁₀, V₁₅, V₂₀ for the parotid gland decreased significantly in FB-WBRT (p < 0.05). The Dmax and Dmean of lens decreased according to the dose-volume histogram. CONCLUSION: Compared to B-WBRT, FB-WBRT with a tilting baseplate is a simple and effective method that takes feature of noncoplanar beam to protect the parotid gland.
Subject(s)
Humans , Brain , Head , Methods , Neoplasm Metastasis , Parotid Gland , Radiotherapy , Skull , Supine PositionABSTRACT
Objective To explore the intensity of coplanar arc-adjusted radiotherapy with volume-modulated arc therapy (VMAT) and whether the position of the head tilt influences the distribution of radiotherapy dose.Methods From 2015 to 2017,500 patients underwent radiotherapy of the head and kept their head tilted.The simulated non-inclined CT images were obtained by rotating the original CT images.The protocol of the coplanar VMAT whole brain irradiation was 30 Gy and the maximum dose of planning target volume in the hippocampus was limited to 16 Gy.The doses of the optic nerve,optic chiasm and eyeball were lower than 37.5 Gy.The dosimetric parameters of two different protocols were statistically compared by paired t-test.Results The average head tilt angle was (11.12°±0.68°).The homogeneity and the conformal index in the tilted and non-tilted positions were decreased by (8.3±9.6) ％(P=0.033) and (5.2±4.1)％(P=0.009).The dose of hippocampus in the tilted position of the head was decreased by (13.6±6.2) ％ on average compared with that in the non-inclined position (P=0.004).The dose of the lenses was decreased by (15.5±11.1)％(P=0.008) on average.The doses of optic nerve and eyeball were declined by (6.8±5.6) ％(P=0.013) and (8.6±6.5) ％(P=0.016).Conclusions By tilting the head at an appropriate angle during VMAT whole-brain radiotherapy,the radiation dose distribution of the target volume can be significantly improved and the radiation dose in the hippocampus and visual system can be reduced simultaneously to maintain the therapeutic effect and minimize the effect upon the cognitive and memory function of patients.
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About 15% to 20% of patients with small cell lung cancer(SCLC)have brain metastases at the time of initial di-agnosis,and more than 80% of patients eventually develop brain metastases. Whole brain radiotherapy(WBRT) is the standard treat-ment for brain metastases in lung cancer. Whole brain prophylactic irradiation(PCI)is an effective treatment for preventing brain me-tastases in SCLC. With the improvement of treatment technology and the standard of treatment,the survival of SCLC patients is pro-longed. The use of spiral tomography(TOMO) technology for hippocampal-protected WBRT in PCI or brain metastasis can reduce neurocognitive impairment and improve the life quality of patient.